Mystery noises in engine bay

[Wing Bucket]

Hi everyone,

The 01 Suburban just started making an couple odd noises under the hood.... 5.3L, 4x4.

One sounds like a whirring motor to me, or a fast clicking. This can be heard on top the engine, near the air intake. The other sort of sounds like a bad bearing. Like metal spinning on metal, but not grinding. This seems to be coming from lower, like near the power steering pump. Neither gets louder or changes with acceleration.

Seems like no change in drivability, acceleration, etc.

Here’s a video of the first/whirring/clicking noise. You can hear right after the engine is turned off, about the 5-6 second mark.

Any ideas?

 

[iamdub]

Hi everyone,

The 01 Suburban just started making an couple odd noises under the hood.... 5.3L, 4x4.

One sounds like a whirring motor to me, or a fast clicking. This can be heard on top the engine, near the air intake. The other sort of sounds like a bad bearing. Like metal spinning on metal, but not grinding. This seems to be coming from lower, like near the power steering pump. Neither gets louder or changes with acceleration.

Seems like no change in drivability, acceleration, etc.

Here’s a video of the first/whirring/clicking noise. You can hear right after the engine is turned off, about the 5-6 second mark.

Any ideas?

Looks to coincide with the spinning of the fan. Fan clutch or water pump bearings wearing out?

Spin the fan by hand to listen for sounds and feel for play. Pull the belt off of the water pump pulley and spin the fan again to spin the water pump pulley to, again, listen and feel.

 

[OR VietVet]

THIS^^^^^^^. Definitely in that area and fan clutch area related. When you spin by hand may feel a roughness from fan clutch and like @iamdub said, take the belt off and check for bearing feel and play.

 

[Wing Bucket]

Thanks for the input. I just spun the fan with the belt on and then took the belt off and spun again. I tried wiggling the fan and it’s pulley and don’t feel any play. I also can’t get it to make any noise.

I spun and wiggled the alternator, power steering pump, and idler pulleys. The only one that makes any noise is the idler pulley. Here’s a video:

The water pump [Eastern] and alternator [AC Delco] both have less than 2000 miles on them. The truck itself has 210k miles.

I don’t know if the fan clutch has ever been replaced....

 

[iamdub]

Thanks for the input. I just spun the fan with the belt on and then took the belt off and spun again. I tried wiggling the fan and it’s pulley and don’t feel any play. I also can’t get it to make any noise.

I spun and wiggled the alternator, power steering pump, and idler pulleys. The only one that makes any noise is the idler pulley. Here’s a video:

The water pump [Eastern] and alternator [AC Delco] both have less than 2000 miles on them. The truck itself has 210k miles.

I don’t know if the fan clutch has ever been replaced....

You might not be able to spin it fast enough. Also, the fan has a thermal clutch so its engagement will vary with temperature. By the time you got to messing with it, it could've cooled enough to lose pretty much all drag, making the sound impossible to replicate.

Your first post suggests that there's two separate noises you're hearing. I could only hear the noise at the end with the engine shut off and the fan slowing down. I'm 100% convinced that one, if not all of the noises you're hearing is related to the fan clutch. Idler pulley slack and noise is somewhat normal, but yours sounds a bit excessive. It would be a cheap start to fixing the possible other noise as well as good preventative maintenance.

Also, aftermarket water pumps for these things don't have a very strong track record. They seem to last just past their warranty period with normal, daily use. So, it's sure to surpass the warranty period if you don't drive much. Of course, this means it'll fail on your first road trip.

 

[OR VietVet]

That idler pulley is bad and while apart, I would do the fan clutch, especially since you think it is original. That idler is under way more stress and will be noisier under load than with the hand. If you have the money, while it is apart, do the tensioner as well. Hell do all of them and belts too. I love spending OPM!

 

[Wing Bucket]

You might not be able to spin it fast enough. Also, the fan has a thermal clutch so its engagement will vary with temperature. By the time you got to messing with it, it could've cooled enough to lose pretty much all drag, making the sound impossible to replicate.

Your first post suggests that there's two separate noises you're hearing. I could only hear the noise at the end with the engine shut off and the fan slowing down. I'm 100% convinced that one, if not all of the noises you're hearing is related to the fan clutch. Idler pulley slack and noise is somewhat normal, but yours sounds a bit excessive. It would be a cheap start to fixing the possible other noise as well as good preventative maintenance.

Also, aftermarket water pumps for these things don't have a very strong track record. They seem to last just past their warranty period with normal, daily use. So, it's sure to surpass the warranty period it if you don't drive much. Of course, this means it'll fail on your first road trip.

I hear you on the road trip comment.... Amazing how that works!

Regarding the second noise, I can’t get it to come through on video unfortunately. It started at the exact same time as the first noise, so I assume they’re related. Looks like a tensioner/pulley and fan clutch replacement are in my near future....

 

[Wing Bucket]

That idler pulley is bad and while apart, I would do the fan clutch, especially since you think it is original. That idler is under way more stress and will be noisier under load than with the hand. If you have the money, while it is apart, do the tensioner as well. Hell do all of them and belts too. I love spending OPM!

Thanks, I’ll be replacing the fan clutch and tensioner/pulley. But will have to stop there for now! Haha

 

[Fless]

When doing the fan clutch, try to use OE if available. We hear stories about aftermarket fans that tend to roar. Also inspect fan blades for cracks.

The fan clutch threads should be right-hand style, so remove in the usual counter clockwise direction.

If you change the water pump, buy one with the thermostat and housing as a set. Sometimes the pumps are different and the old thermostat housing doesn't fit the new pump.

 

[Wing Bucket]

When doing the fan clutch, try to use OE if available. We hear stories about aftermarket fans that tend to roar. Also inspect fan blades for cracks.

The fan clutch threads should be right-hand style, so remove in the usual counter clockwise direction.

If you change the water pump, buy one with the thermostat and housing as a set. Sometimes the pumps are different and the old thermostat housing doesn't fit the new pump.

Great tips, thank you